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Monday, February 13, 2017

California bureaucrats rejected cement upgrades to Oroville Dam more than a decade ago. Emergency spillway of the state's second largest reservoir was allowed to remain a vulnerable earthen hillside-Mercury News, 2/12/17

The groups filed the motion with FERC, the Federal Energy Regulatory
Commission. They said that the dam, built and owned by the state of
California, and finished in 1968, did not meet modern safety standards
because in the event of extreme rain and flooding, fast-rising water
would overwhelm the main concrete spillway, then flow down the emergency
spillway, and that could cause heavy erosion that would create flooding
for communities downstream, but also could cause a failure, known as
“loss of crest control.”...

Those
agencies included the Metropolitan Water District of Southern
California, which provides water to 19 million people in Los Angeles,
San Diego and other areas, along with the State Water Contractors, an
association of 27 agencies that buy water from the state of California
through the State Water Project. The association includes the
Metropolitan Water District, Kern County Water Agency, the Santa Clara
Valley Water District and the Alameda County Water District.

Federal officials at the time said that the emergency spillway was
designed to handle 350,000 cubic feet per second and the concerns were
overblown.

“The emergency spillway meets FERC’s engineering guidelines for an
emergency spillway,” he added. “The guidelines specify that during a
rare flood event, it is acceptable for the emergency spillway to sustain
significant damage.”

This weekend, as Lake Oroville’s level rose to the top and water
couldn’t be drained fast enough down the main concrete spillway because
it had partially collapsed on Tuesday, millions of gallons of water
began flowing over the dam’s emergency spillway for the first time in
its 50-year history.

Such an uncontrolled release from California’s second-largest
reservoir while it was completely full could become one of the worst dam
disasters in U.S. history....Lester Snow, who was the state Department of Water Resources director
from 2004 to 2010, said Sunday night that he does not recall the
specifics of the debate during the relicensing process 11 years ago.

“The dam and the outlet structures have always done well in tests and
inspections,” Snow said. “I don’t recall the FERC process.”...

A filing on May 26, 2006, by Thomas Berliner, an attorney for the
State Water Contractors, and Douglas Adamson, an attorney for the
Metropolitan Water District of Southern California,discounted the risk.
It urged FERC to reject the request to require that the emergency
spillway be armored, a job that would have cost tens, if not hundreds,
of millions of dollars.

“The emergency spillway was designed to safely convey the Probable
Maximum Flood, and DWR has reviewed and confirmed the efficacy of the
PMF hydrologic analysis for Oroville Reservoir,” the attorneys noted.

Ultimately, they were successful. FERC did not require the state to upgrade the emergency spillway."